code: def test_loader(self):
      if ok_ljspeech:
          dataloader, dataset = self._create_dataloader(2, c.r, 0)
  
          for i, data in enumerate(dataloader):
              if i == self.max_loader_iter:
                  break
              text_input = data[0]
              text_lengths = data[1]
              speaker_name = data[2]
              linear_input = data[3]
              mel_input = data[4]
              mel_lengths = data[5]
              stop_target = data[6]
              item_idx = data[7]
  
              neg_values = text_input[text_input < 0]
              check_count = len(neg_values)
              assert (
                  check_count == 0
              ), " !! Negative values in text_input: {}".format(
                  check_count
              )
              # TODO: more assertion here
              assert isinstance(speaker_name[0], str)
              assert linear_input.shape[0] == c.batch_size
              assert linear_input.shape[2] == self.ap.fft_size // 2 + 1
              assert mel_input.shape[0] == c.batch_size
              assert mel_input.shape[2] == c.audio["num_mels"]
              # check normalization ranges
              if self.ap.symmetric_norm:
                  assert mel_input.max() <= self.ap.max_norm
                  assert (
                      mel_input.min() >= -self.ap.max_norm
                  )  # pylint: disable=invalid-unary-operand-type
                  assert mel_input.min() < 0
              else:
                  assert mel_input.max() <= self.ap.max_norm
                  assert mel_input.min() >= 0
  
file_path: TTS/tests/test_loader.py
imports: import os
  import shutil
  import unittest
  import numpy
  import torch
  from tests import get_tests_input_path, get_tests_output_path
  from torch.utils.data import DataLoader
  from TTS.tts.datasets import TTSDataset
  from TTS.tts.datasets.preprocess import ljspeech
  from TTS.utils.audio import AudioProcessor
  from TTS.utils.io import load_config
label_desc: Use image node_id 3 for calling the TestTTSDataset obj's underlying member method code with example usage: obj.test_loader() without return types